Evolution of structural and dynamic heterogeneities during elastic to plastic transition in metallic glass
Evolution of structural and dynamic heterogeneities during elastic to plastic transition in metallic glass
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DOI：
10.1063/1.4933343
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发表时间：
2015-10
影响因子：
3.2
通讯作者：
Liyun Zhao;Yun-liang Li;R. Xue;Wen-Qiong Wang;H. Bai
中科院分区：
文献类型：
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作者：
Liyun Zhao;Yun-liang Li;R. Xue;Wen-Qiong Wang;H. Bai
研究了典型金属玻璃（MG）在恒定应变作用下表观弹性区的微观局部化流动演化。采用活化-弛豫方法，得到了MG中活化流动单元的能垒和弛豫时间谱随时间的分布和演化规律。结果表明，玻璃中作为流动单元的不稳定纳米级类液区可被外力激活，当流动单元比例达到临界逾渗值时，其随时间的演化呈现出从局部激活到级联激活的过渡过程.流动单元的演变导致了机械的弹塑性转变或宏观塑性流动。一个合理的图表涉及时间，应力和温度的建立，以了解变形和流动机制的MG，并可以提供见解的玻璃性质，流动单元，以及它们与变形行为的MG有趣的困境。
We investigate the evolution of microscopically localized flow under a constant applied strain in apparent elastic region of a prototypical metallic glass (MG). The distribution and evolution of energy barriers and relaxation time spectra of the activated flow units in MG with time are obtained via activation-relaxation method. The results show that the unstable nano-scale liquid-like regions acting as flow units in the glass can be activated by external stress, and their evolution with time shows a crossover from localized activation to cascade as the proportion of the flow units reaches a critical percolation value. The flow unit evolution leads to a mechanical elastic-to-plastic transition or macroscopic plastic flow. A plausible diagram involved in time, stress, and temperature is established to understand the deformations and the flow mechanisms of MGs and could provide insights on the intriguing dilemmas of glassy nature, the flow units, and their correlations with the deformation behaviors in MGs.